Hazardous waste from chemical factories including fluorine and chlorine has rather low fusion temperatures. During incineration in a rotary kiln incinerator, hazardous waste including fluorine and chlorine melts and turns into slag, possibly adhering to the inner wall and leading to unstable operation of the incinerator. Prediction of the melting characteristics of hazardous waste including fluorine and chlorine hence plays an important role in preventing slagging. The effect of various chemical components on fusion temperatures (deformation temperature, DT; softening temperature. ST; hemisphere temperature, HT; and flow temperature, FT) has been investigated experimentally: Na(2)O and NaF are the most remarkable chemical compounds among those investigated. Correlations between fusion temperatures and chemical components have been investigated; neural networks have been used to predict four characteristic melting temperatures and are verified by tested slag samples of hazardous waste including fluorine and chlorine. Relative errors of fusion temperatures (computed vs. measured) are mostly less than 1.2%. (C) 2011 Elsevier B.V. All rights reserved.